Gold Member

Recently, I've been researching heavily the topic of fungi... which eventually led me to think about algae.

My question is based on a scenario as follows: If I were to leave a large jar of water sitting out in a room for a long enough period of time, it would start to form algae along the glass. However, if matter cannot be created or destroyed, from where did that algae originate? Is it already in the tap water or air, simply waiting for the proper moment to manifest?

Well, if your scenario indeed uses tap water inside the jar, then algae will never form. Tap water is chlorinated and would kill any waterborne inhabitants, unless the water was first left sitting out until the chlorine dissipated (~two days).

Which then begs the question of whether the jar is sealed or not. Again, if it's open, then the chlorine which inhibits the growth of algae can dissipate, and moreover, airborne algae spores can enter the jar and multiply, if the jar is exposed to adequate light.

In the Renaissance, the theory of Spontaneous Generation was tested by putting a hunk of rotting meat in a "sealed" room. When they found maggots in it days later, it was considered "proof" that organisms could spawn from nothing. I suspect that like their flawed experiment, your jar is not wholly sealed, allowing chlorine to get out and spores to get in.

Gold Member

Well, if your scenario indeed uses tap water inside the jar, then algae will never form. Tap water is chlorinated and would kill any waterborne inhabitants, unless the water was first left sitting out until the chlorine dissipated (~two days).

Which then begs the question of whether the jar is sealed or not. Again, if it's open, then the chlorine which inhibits the growth of algae can dissipate, and moreover, airborne algae spores can enter the jar and multiply, if the jar is exposed to adequate light.

In the Renaissance, the theory of Spontaneous Generation was tested by putting a hunk of rotting meat in a "sealed" room. When they found maggots in it days later, it was considered "proof" that organisms could spawn from nothing. I suspect that like their flawed experiment, your jar is not wholly sealed, allowing chlorine to get out and spores to get in.